Medical imaging of breast tissue can, among other things, assist the detection and delineation of breast cancers. Various medical imaging scans, such as MRI imaging scans and/or ultrasound imaging scans, provide data for the detection of potential suspicious regions in breast tissue where an intervention, such as, for example, a biopsy may be performed.
In some imaging systems it can tend to be important that the imaging apparatus is as close as possible to the surface of the tissue being imaged. For example, in MRI imaging the closer the receiving coils are to the tissue surface, the signal-to-noise ratio tends to be improved. In another example, for ultrasound imaging, it may be important that there is direct contact or contact without airspace between an ultrasound probe and a breast tissue surface, and so it can tend to be important to have an ultrasound probe pressed directly, or as closely as possible to the tissue, or, in some examples, an ultrasound permeable material in direct contact with the tissue.
In certain immobilization apparatuses, there are two sterile compression plates, one on each of the medial and lateral sides of a patient's breast, to immobilize the breast tissue while the patient lies in the prone position. Such approaches tend to not allow the geometric relationship between the apparatus, the breast tissue and the torso of the patient to be maintained if the patient moves out of the imaging position, for example if they were to stand up and move about the imaging facility. Additionally, in such exemplary immobilization apparatuses, the compression plates frequently do not conform exactly to the shape of the breast and as such, all surfaces of the breast may not be accessible for a subsequent image, such as an ultrasound, or for delivery of an interventional instrument, such as, for example, a biopsy needle, when performing a biopsy or image-guided intervention. Additionally, these immobilization apparatuses may apply pressure on a patient's breast tissue which may cause discomfort to the patient.
It can also tend to be advantageous for improving workflow in medical imaging facilities to allow patients to easily change positions while being imaged. It may further be advantageous to allow patients to stand up and walk away from imaging systems, such as MRI systems, while immobilizing and/or stabilizing the breast in a known geometry (such as a held position and shape), and/or maintaining a fixed geometric relationship between the breast and the torso of the patient. In such applications it can be advantageous to limit the extent to which the tissue being imaged, such as a breast, may change positions or shape when a patient moves during an imaging procedure in order to maintain an approximately constant relationship between the geometry of the patient's breast and the previously acquired imaging data. Additionally, it may be desirable to be able to co-register multiple images from the same imaging systems, such as multiple MRI images acquired using different pulse sequences, or to co-register multiple images from different imaging systems, such as MRI images and ultrasound images. It may be necessary to minimize changes in the geometric position of a breast relative to the torso or relative to the immobilization device as a patient changes positions or moves to a different location in a medical imaging facility, which can tend to improve the accuracy and/or ability to co-register different images of the breast.